Karad SN, Chung WK, Liu RS. Gold-catalyzed formal [4π + 2π]-cycloadditions of propiolate derivatives with unactivated nitriles.
Chem Sci 2015;
6:5964-5968. [PMID:
29861918 PMCID:
PMC5950837 DOI:
10.1039/c5sc01950h]
[Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 07/17/2015] [Indexed: 11/29/2022] Open
Abstract
Gold-catalyzed hetero-[4π + 2π]-cycloadditions of tert-butyl propiolates with unactivated nitriles are described. This new finding enables a one-pot gold-catalyzed synthesis of highly substituted pyridines.
Gold-catalyzed hetero-[4π + 2π]-cycloadditions of tert-butyl propiolates with unactivated nitriles are described; the resulting 6H-1,3-oxazin-6-ones are not easily accessible via conventional methods. This new finding enables a one-pot gold-catalyzed synthesis of highly substituted pyridines through sequential gold-catalyzed reactions of tert-butyl propiolates with nitriles, and then with electron-deficient alkynes in the same solvent. The utility of these [4 + 2]-cycloadditions is further expanded with various aldehydes, ketones and 2-phenyloxetane, yielding satisfactory yields of cycloadducts.
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